Untangling the Complex Web of Human Mobility

Migration is one of the most dynamic and politically salient demographic processes, yet establishing clear cause-and-effect relationships is notoriously difficult. Do job-training programs in origin regions reduce emigration, or do they equip people to migrate more successfully? Does granting legal status to immigrants improve their long-term economic integration? The Institute of Experimental Demography tackles these questions head-on by exploiting natural experiments. We systematically identify and analyze events that create quasi-random variation in migration determinants, such as sudden policy changes (visa lotteries, amnesties, border enforcement shifts), economic shocks (factory closures, commodity price booms), or environmental disasters (droughts, floods). This approach allows us to move beyond descriptive patterns to estimate the causal effects of specific factors on migration decisions, flows, and outcomes for both migrants and sending/receiving communities.

Causal Evidence on Drivers and Deterrents

A major research stream focuses on policy-induced migration. For example, we have studied the demographic and labor market effects of a unilateral decision by a country to open its borders to workers from a specific set of nations. By comparing trends for eligible and ineligible source countries, we can isolate the impact of the policy itself from broader global trends. Similarly, we use the random lottery system of some visa programs as a perfect natural experiment to study the long-term trajectories of 'winners' versus 'losers,' providing unambiguous evidence on the benefits of migration for individuals and their families.

Another key area is environmentally induced displacement. Rather than simply correlating drought severity with migration rates—which could be confounded by poverty or governance—we focus on specific, unexpected climatic events or the introduction of new irrigation technologies. This allows us to estimate how much a given change in environmental conditions directly causes migration, and importantly, what type of migration (temporary, permanent, internal, international). Our work has shown that the relationship is highly nuanced; sometimes environmental stress traps populations rather than displacing them, depending on asset levels and mobility costs.

We also conduct survey and field experiments in migrant-sending communities. These experiments test how providing accurate information about job prospects, risks, and legal pathways influences migration intentions and preparations. This research helps design more effective and ethical information campaigns.

• The Border Policy Shock Project: Analyzes demographic and humanitarian outcomes of sudden changes in border enforcement strategies using a difference-in-differences framework.
• Refugee Integration RCT: Partners with resettlement agencies to randomly assign new arrivals to different support programs (e.g., intensive language training vs. rapid job placement) and tracks long-term integration.
• Remittance Channels Experiment: Tests how reducing transaction costs for sending remittances affects the amount sent and its use for investment in origin communities.
• Network Effects Study: Uses the staggered migration of siblings as a natural experiment to measure the causal effect of existing migrant networks on the likelihood and success of subsequent migration.

From Evidence to Ethical Policy

The ultimate goal of our migration research is to replace speculation with evidence in public and policy debates. Our findings have been used to design more effective integration programs, evaluate the humanitarian impact of border policies, and assess the development potential of diasporas. A critical ethical dimension of our work is giving voice to migrant experiences. Our mixed-method approaches combine causal quantitative analysis with in-depth qualitative interviews to understand the subjective meanings and challenges of mobility. Looking ahead, we are developing novel methods to use high-frequency digital data (like mobile phone network movements) to track displacement in near-real-time during crises, while rigorously protecting privacy. By grounding our understanding of migration in rigorous causal evidence, the Institute of Experimental Demography aims to foster policies that are not only effective but also humane, recognizing migration as a fundamental human adaptation to changing circumstances and an engine of societal renewal.